0794 Normative Transcutaneous Carbon Dioxide (TCCO2) Values in Older Children

Abstract Introduction Transcutaneous carbon dioxide monitoring (TCCO2) is being increasingly used in pediatric sleep studies to assess for hypoventilation. However, consensus is lacking on a pediatric definition for hypoventilation. This study evaluates the applicability of adult hypoventilation definitions to healthy older children. Methods Subjects, 10 years to 18 years of age, participating in a study on sleep EEG dynamics in typical developing children were included. All participants underwent an in-lab nocturnal polysomnography with Natus Sleepworks TM system and following American Academy of Sleep Medicine (AASM) guidelines. Sentec monitor (Therwil, Switzerland) was used for TCCO2 recording. Studies were scored according to the AASM pediatric criteria. Nocturnal hypoventilation was evaluated according to the following definitions: – Over 25 percent of sleep time with a TCCO2>50 mmHg [AASM], – A peak of TCCO2>50 mmHg [S Ward, 2005], – A percentage of nighttime with a TCCO2>50 mmHg>2 % [R Paiva, 2009], – A TCCO2>10 mmHg above the morning awake minimal TCCO2 level [FJ O’Donoghue, 2003]. Results Preliminary results on 7 subjects of which 71 % were females are presented. The mean age was 14.7 years (SD 2.6 years) and mean BMI was 22.2kg/m2 (SD 2.3). All subjects had an obstructive AHI of < 1; Mean awake TCCO2 was less than 45; Mean asleep TCCO2 was less than 50. There were no subjects with TCCO2 values >50 for over 25 % time or with delta TCO2 sleep to awake of >10 mmHg. There was one subject with peak TCCO2 values>50 and one subject withTCCO2 values >50 for 15 % time. Conclusion Our results, with no healthy child having >25 % of sleep time with TCCO2 over 50 mmHg, support the use of AASM hypoventilation definition in older children. When validity of AASH hypoventilation criteria is questionable due to sleep time < 4 hours or low REM sleep fraction, then an increase of sleep CO2 of 10 units as compared to awake values may also be used to identify hypoventilation. Support (if any) Research Institute, Nationwide Children's Hospital